#include<stdio.h>
#define PI 3.1415927
int main()
{
	double r, volumetric;

	while (scanf("%lf", &r) !=EOF){
		volumetric = 4.0*PI*r*r*r/3.0;
		printf("%.3lf\n", volumetric);
	}
	
	return 0;
}
